Formation evaluation in thinly-bedded sands has always been a challenge especially as individual sand beds thin below the resolution of logging tool measurements. Evaluation of these reservoirs is often further complicated since the various log measurements have differing vertical resolutions and depths of investigations and the wells normally have somewhat disparate log datasets.
In this study of a field located in the Gulf of Mexico (GoM) Deepwater the authors will demonstrate how a consistent and cross-verified approach was taken to evaluate thinly-bedded sands which resulted in increasing interpretation confidence and a more realistic net pay when compared with prior techniques that utilized conventional log interpretations.
The field for this study has a total of five wells including one well with whole core, three wells with nuclear magnetic resonance (NMR) logs, including the cored well, and two wells with standard log suites. The methodology applied begins with creating a continuous sand count curve from the visual evaluation of whole core photographs. This sand count curve is then compared with the net-to-gross (NTG) curve obtained from a Thomas-Stieber analysis and then cross-verified via NTG obtained from a NMR log. The calibration from the three wells with whole core or NMR was applied to the Thomas-Stieber analysis performed on the two wells with standard suites of logs. Whole core porosities and water saturations are then used to constrain the log-derived porosity and water saturation values. Finally saturation height modelling has been performed using porous plate capillary pressure data and compared to log-derived water saturations.
This paper provides an overview of the Delta House Project. The Delta House Floating Production System (FPS) in located in the Mississippi Canyon protraction area of the Gulf of Mexico in block 254 and will initially process production from three "anchor" fields varying from six to fourteen miles from the FPS. The FPS uses the Exmar Offshore designed OPTI-1100® semisubmersible design which has a nameplate capacity of 80 MBOPD and 200 MMCFD with peaking capacity of 100 MBOPD and 240 MMCFD. The Delta House anchor fields are primarily oil bearing Miocene sands in a channel levee turbidite depositional environment. Seven wells have been drilled to date in the initial anchor fields. Each anchor field will be developed with (i.e. wet trees) flowing to subsea manifolds and subsequently to the FPS via two infield flowloops using steel catenary risers. The project includes a 12" oil export line and 16" gas export line using steel catenary risers.
There are several unusual aspects of the Delta House project. The project went from first discovery to first production in about three years which is significantly less than other projects involving a new FPS. Engineering for the FPS and bidding of construction yards began prior to the first Delta House discovery. The Delta House FPS and export lines are owned by special purpose entities funded primarily by private equity.
This paper will provide a history of the project and will highlight the reasons for some of the key decisions that were made throughout the development.
Elebiju, Bunmi (BP America) | Ariston, Pierre-Olivier (BP America) | van Gestel, Jean-Paul (BP America) | Murphy, Rachel (BP America) | Chakraborty, Samarjit (BP America) | Jansen, Kjetil (BP America) | Rodenberger, Douglas (Shell America) | White, Roy C. (Shell America) | Chen, Yongping (CGG) | Hren, David (CGG) | Hu, Lingli (CGG) | Huang, Yan (CGG)
Using the Kepler and Ariel Fields as a case study, this paper discusses the processing challenges and solutions applied to a 4D co-processing of Wide Azimuth Towed Streamer (WATS) on Narrow Azimuth Towed Streamer (NATS) data. Unlike a dedicated 4D acquisition, WATS on NATS 4D has relatively low repeatability in terms of acquisition geometry and bandwidth differences. All these factors can negatively impact the extraction of a meaningful 4D signal. In this paper, we demonstrate how processing techniques can help to increase repeatability and enhance 4D signal. We focus on the following 4D processing procedures: 4D co-binning, data matching, and post-migration co-denoise. Due largely to these techniques, the final co-processed volumes show an optimized 4D seismic signal with a median Normalized Root Mean Square (NRMS, which measures the repeatability between base and monitor. Details refer to Kragh and Christie, 2002) of 0.10 along the water bottom and 0.28 above the reservoir.